RESUMO
Red maple (Acer rubrum) and silver maple (A. saccharinum) are sister species that readily hybridize in nature. No genetic or barcoding markers have been tested in these species. The main objective of the present study is to develop and characterize molecular markers for distinguishing A. rubrum and A. saccharinum and to validate the hybridity of A. freemanii derived from their crossings using the ISSR marker system. Thirteen A. rubrum and seven A. saccharinum populations were used. Four ISSR primers including ISSR 5, ISSR 8, ISSR 10, and ISSR UBC 825 were selected to amplify genomic DNA from the two species and their hybrids. Each primer generated at least one species-diagnostic ISSR marker for a total of six. Analysis of A. freemanii collected from North Dakota (USA) confirmed that the genotypes screened were true hybrids between A. rubrum and A. saccharinum. These markers were cloned and sequenced. Successful sequences were converted to SCAR markers using specifically designed primers. Overall, the developed diagnostic and specific ISSR and SCAR markers are useful in the certification of these two maple species and their hybrids. They can be used in tracking the introgression of A. rubrum and A. saccharinum DNA in other hybrid trees or populations.